Auxiliary preheating element in boilers for quick steaming and heating



Aug. 4, 1942. R. H. ROBINSON AUXILIAR'I PREHEATING ELEMENT IN BOILERS FOR QUICK STEAMING AND HEATING Filed may 27, 1957 3 Sheets-Sheet l g- 4, 1942- R. H. ROBINSON 2,291,921

ERS FOR QUICK sTEAMINe AND HEATING AUXILIARY PREHEATING ELEMENT IN BOIL Filed May 27, 1957, 5 Sheets-Sheet 2 4, 1942. R. H. ROBINSON 2,291,921

AUXILIARY PREHEATING ELEMENT IN BOILERS FOR QUICK STEAMING AND HEATING Filed May 27, 1937, 3 Sheets-Sheet 3 Patented Aug. 4-, 1942 UNETED STATES -AUXIIIARY PREHEATING ELEMENT IN BOILER-S FOR QU HEATING ICK STREAMING AND 11 Claims.

This invention relates to improvements in boilers for heating and steaming plants and introduction into their firebox or combustion chambers of quick heating elements formed of metal of high conductivity such as copper and copper x alloy so designed and located and so connected with the water jackets and steam chambers of the boiler as to produce exceptionally rapid heating and pre-steaming, particularly in connection with automatic firing devices 'suchas coal stokers,.

oil burners, gas burners and the like now in use.

These and the many other objectives and advantages of my invention are better understood by referring to the following specifications when considered in connection with the accompanying drawings illustrating certain embodiments thereof in which:

Fig. 1 is a transverse sectional elevation through the fire box of a typical boiler showing" the installation of my conically formed presteaming elements.

Fig. 2 is a longitudinal sectional elevation of same.

Fig. 3 is a sectional view of oneof the conical" pre-steaming elements attached to the walls of the water jacket of the boiler.

Fig. e is a front elevation of an alternate presteaming coil of either fiat or concave disc forma- 1 tion.

Fig. 5 is a side elevation of same.

Fig. 6 is a side elevation of same in the more concave form.

Fig. 7 is another transverse sectional elevation through the The box of a typical boiler showing tion through the fire box of a typical boiler showing still another arrangement of the presteaming improvement.

Fig. 11 is a fragmentary longitudinal sectional view through same at the end where same attaches to the water jacket at the boiler.

Fig. 12 is a cross-section through one of the pre-steaming finned and coiled tubes shown in Figure 10 as on section line l2|2 of Figure 11.

Fig. 13 is a side elevation of a modified form of the pre-steaming element attached to the water jacket of a typical boiler.

Fig. 14 is a front elevation of same.

Fig. 15 is a perspective showing a further modified form of pre-steaming elements as attaching to the sides of the water jacket of the boiler fire box.

Fig. 16 is a fragmentary perspective of a modified form of my pre-steaming improvement combining multiple steaming units in a single frame.

Fig. 17 is a sectional side elevation of same as attached to the water jacket wall of a typical boiler.

Fig. 18 is a side elevation of a modified form of pre-steaming elements attached to the water jacket of a boiler.

Fig. 19 is a cross-section taken on the line l'9-I9 of Figure 18.

Fig. 20 shows a modified form of my presteaming elements arranged for another form of typical boiler showing same fired by gas or oil.

Referring to the drawings in detail and more particularly to drawings 1 to "6 inclusive, the water jacket I with the inside Wall l encloses the fire box or combustion-chamber 5 of one of the typical boilers on the market in the customary manner. The fire box 5 is fired in this instance by one of the typical underfeed coal stokers, the coal 2 being fed into the fire pot 2 by the screw 3 and combustion secured through the forced air draft blown through the twyers 4. It is to be understood that the improvements presented by my invention are not confined to any particular form of boiler or firing of same, and can be used with either oil, gas, or mechanically stoked coal, and also with hand firedfuel, but my improvements are particularly suited to the mechanically controlled form of firing covered by oil and gas burners and coal stokers.

Connected with the fire box 5 are the boiler tubes 6 and above the fire box the crown sheet I. The water 8 fills the boiler to the water level 9 and above same is the steam chamber 1%], the steam outlet occurring at H with a check valve l'2, if desired; controlling same. A vacuum pump I3 draws the steam through the system through the pipe 13 and the return water returns to the boiler through the line 53 The vacuum pump gives enhanced efficiency wi'th my improvement,

but can beomitted if desired.

In order to secure the best results, I provide a special wall Hi as a novel feature, building same-across the fire box 5 preferably nearer'the end closest to the boiler tubes as noted and 5 located between the stoker fire pot 2 and the openings of the boiler tubes 6.

As indicated in Figures 1 and 2, I build this wall, in this instance, of fire brick or suitable refractory material, and at a predetermined and proper location in this wall, I provide a control exit opening l5 of relatively small size in proportion to the size of the fire box. This is preferably located on the central axis and at a height predetermined for the desired results. By thus introducing this intercepting wall, I prevent the forced draft coming from the stokcr twyers 4 from escaping directly and immediately into the tubes 6 towards which they are violently drawn by the strong suction of the chimney, and instead I confine, retain and delay them in the fire box and then permit them only to escape slowly and in compression through the restricted opening 15, thereby securing a more perfect and complete combustion within the fire box and bringing the hot air and the cold air which escapes through blow holes inherent in stoker forced draft firing, together in a compressed mass producing a unified mixture and perfect combustion before the burning gases reach the boiler tubes. As already noted, this does away with the common difiiculty of cold air from blow holes in the fire being sucked directly into the lower tubes only to chill the boiler while the hotter incompletely oxidized gases rush upward passing through the upper tubes without proper or complete oxidation. This difficulty is a common fault in boilers using these stokers with the consequent chilling of the boiler, excessive waste of fuel and poor steaming.

The further important purpose of my wall [4 with my restricted outlet 15 is to control and direct the path of combustion and this partcularly in relation to my pre-steaming cones 16, which I install as noted on the sides of the water jacket surrounding the fire box and where desired, on the crown sheet I of same. By means of the opening I5, I draw the burning gases close the coil forming the cone Hi the tubular intake 20, also preferably round, connects with intake tube 2| within the water jacket of the boiler and this tube extends upward to a point slightly below the water level in the boiler or slightly above the crown sheet 1, which it will be understood is obviously always kept covered with a protective layer of water. Thus I draw the intake water directly from upper water having the very highest temperature and feed this hottest water directly into the pre-steaming cone and circulate it in the cone to bring it to a steaming temperature and then pass it out as steam directly into to the heating cones and in proper proximity thereto so that the gases are neither chilled too much before combustion is secured, or are too far away from the steaming cones to prevent the cones from absorbing the maximum amount of heat as same is emitted. In this connection it will be particularly noted that I tilt the cones attached to the sides of the firebox toward the core of the fire at a properly determined degree. In most instances this will be such that the central axis of the cone is at an angle between 30 and 60 to the horizontal bed of the fire box. This angle, however, it will be understood will be varied according to conditions and as results dictate.

The cones I6 I form in various ways, but in the preferred form shown in Figure 3, I use a tube I! of preferably rectangular cross-section terminating in a central stem l8 preferably of round. cross-section and passing through the center of the cone, and by suitable connections anchoring to and connecting with the water jacket I and joined to an outlet tube [9, which extends upward through the water with its final outlet adjacent the water level of the boiler and in most instances slightly above it as indicated. Where preferred, however, this outlet can terminate slightly below the water level, but in either case the purpose of this extended outlet is to carry the steam generated in the tubular walls of the steaming cone directly .to the steam chamber l0 without the steam being exposed to condensation by prolonged passage into and through the colder water of the water jacket I. At the other end of the steam chamber I 0 without it being condensed by extended contact with the water in the water jacket of the boiler, and all this without waiting for the main body of water in the boiler to reach a steaming temperature.

As I have previously emphasized, I tip my heating cones towards the fire and the path of the oxidizing gases at an angle predetermined in connection with the opening l5 and the wall I4. By this means, a maximum amount of heat rays are captured from the burning gases which travel convergingly upward and diagonally forwardtoward the wall outlet l5. Also by this arrangement the gases themselves are trapped and drawn into and through the cones which are open at both ends for this purpose. In addition to tipping the cones downward towards the fire, I also, for the same reason, preferably face them at an angle diagonal to the path of the oncoming gases and furthermore extend them serially outward to form rows converging toward each other from the opposite walls of the fire box and toward the wall opening Hi, all as indicated in Figures 1 and 2. This converging distribution of the heating elements gives wider access to the fire box adjacent the boiler door and also brings the heaters in closer to the path of the burning gases as the combustion becomes more fully completed.

It will be readily seen that the heat rays as well as the gases are captured in the cones and then refracted from all sides within the cone on to the central stem l8 so that a super-steaming heat is quickly developed in the stem I 8. Also, as already noted, the cone has an opening 22 at its smaller and upper end so as to pull the burning gases by draft action through same after they are captured in the large face opening overhanging the fire. Passing through the v decreasing diameter of the cone, the captive about the stem [8 as well as reacting on the side walls of the cone itself. By this means, it will be readily seen that the water entering the tubular stem of the heating cone is subjected to tremendous heating power which the boiler itself in no part possesses.

In addition, to further enhance this efficiency, I preferably provide heat absorbing and stiffening fins 23 which I braze inside and outside of the tubular walls of the cone so that a still greater heat absorption is obtained and this transferred to the tubular cone walls and hence to the water therein. As already set forth, the prime purpose of all this is to quickly generate steam by taking the hottest water in the very top of the boiler and return it as steam directly into the upper steam chamber above the water of the boiler and hence into the heating system of the building. In this way, with this multiple system of cones, as noted, steam in quantity is generated long before the water proper of the boiler has come to a steaming point and the heating pressure is generated and the building heated in advance of the ordinary steaming of the boiler proper. The result of this is that the firing of the boiler, which is controlled in the customary way by automatic steam pressurestats, thermostats or time clocks is limited to much shorter periods of operation and steam distributed much more quickly throughout the heating system. With the operation so shortened, the desired saving of fuel is, of course, obvious. Similarly in extremely cold weather or where the boiler has a large load to carry or is'undersized, much greater efficiency and the possibility of carrying a much heavier load is at once made possible.

Referring further to the fins 23, which are made out of metal of suitable conductivity such as copper or copper chrome or other alloy, these can be shaped and applied in various forms. In this instance, I form them by stamping out the openings for the tubular shell of the cone, folding back the metal to form these openings and at the same time provide thereby alternating feet 24 which lie against the stepped faces of the tubular wall. These also have similar extending feet 25 bent outward at the inner extremity to contact the stem ES. These fins are slit at the end 26 to slip on, and after being slipped on to the coils are brazed in place by exposure to a brazing bath, or other suitable means, and the extending feet of the fins thus become molecularly united to the wall I! forming a solid cone.

It is also understood that the tubing 11 can be coiled either closely or spaced apart, but by spacing it closely so that the edges come in con-' tact, the brazing can also be applied to thesecontacting surfaces at I! and the walls of the cones so entirely brazed together by this means, giving both great strength and stiffness as well as great heat holding and transmitting efficiency.

It is understood that round or other shaped tubing can be used for forming the walls of the cone in lieu of the rectangular tubing, but my novel use of -a fiat rectangular tubing for this gives a much greater heating efficiency, first because the flat surfaces absorb the heat rays hitting against same, where the rounded surface refracts them off, while the water within the tube is heated much faster by having a greater wall area surrounding it for the same cubical contents. and by having a very thin wall of Water between the two wide parallel faces of the tubing, thus producing much quicker heat -absorption and steaming. The tubing can be-rectangular throughout in which-case the fittings receiving same are formed accordingly, but to simplify the construction inthe bending of the tubing, I preferably take a roundtube' and flatten the desired portions by subjecting same to pressure with rollers, dies, or other means, so that the portions form-ing the spiral wall of thecone are rectangular, but the portions forming the stem 18, which has to-be bent upward at the necessary curve from the termination of the coiled wall, I leave round as also the portion forming the terminal 20 at the other end, so that the round tubing can be accommodated to the sharper bends and fit into standardly formed round connections into which they are preferably brazed or joined by other customary means.

The connections between the cone terminals and the water jacket may 'be any suitable arrangement and secured in a flange 2 l welded to the walls of the fire box where same are of steel, or where the boiler is of cast iron the cast iron is drilled and tapped and the connections are screwed into same. The intake and outlet tubes I9 and 2| can be of light metal, copper or otherwise, of thin walls and soft temper sufiiciently pliable so that these can be pushed .through the holes in the sides of the boiler walls and suitably secured to the connections for the coil terminals.

In Figures 4 and 5- is shown a modified form of coiling the tubing, in'this instance to form a disc like shield or cone which can be either practically fiat, slightly concave or more deeply cupped as shown in Figure 6. In this instance,

I have employed round tubing I! for easy bending, the coiling crossing across the face of the disc to form the member 18 in lieu of the stem 18 in'the previous cone. The coiling is rigidly held together by any suitable means and in this instance, I lace same with a light thin pliable brass or copper band 21 and also add I'GiIIfOI'C".

ing fins 23 of sheet copper alloy or other suitable metal of proper thickness, for stiffening the disc and absorbing and transmitting the heat. These fins are similarly provided with bent out feet 24, as before noted, which slip under and between the metal lacing band 21 and the coil I7. After the coil is assembled, it is brazed into a united mass by this means.

It is to be understood that these discs or cupped like cones are attached to the boiler walls in the same manner as my previous cones l6 and also have their faces tipped out diagonally in the fire box and located in similar manner so as to trap and contact the greatest quantity of burning gases and radiant heat rays.

It is to be particularly noted that by providing stiffening fins of stiff alloy with tubing of soft temper where desired I can secure easy shaping and coiling of the tubing while at the same time the finished brazed cone or coil has the necessary rigidity to properly hold its shape and position in the fire box. For the same reason I am able to employ thinner gauge tubing if desired, thereby securing quicker heating of the water in the tubing while having the supporting strength in the stiff fin structure.

Furthermore, my fins make a holding clamp for maintaining the coiling in position during brazing into a structural unit.

It is to be understood that my method of equipping a boiler, as noted above, can be applied to any system of either steam or hot water heat and to a straight line gravity steam heating system. In its preferred form, however, I combine this with a vacuum system pump [3, quickly taking the steam from the pro-steamers into the heating system with a minimum condensation in the steam chamber of the boiler. In this connection, by combining this with a steam check valve l2, the steam can be held in the heating system without backing up and condensing in the boiler, notwithstanding the fact that the boiler proper is not brought to a steam ing temperature, the steam in such instance being produced only by the pre-steamers.

Figures 7, 9 and 10 show modified forms of my pre steaming system in which -finned or finned and coiled pre-steaming members are employed in lieu of the'pre-steaming cones, these being used in similar manner to obtain similar results. In

Figure 7 in boilers similar to that of Figures 1 and 2, I introduce in the boiler box, copper, copper alloy, or other suitable metallic tubes or pipes 28, to which I attach heating fins 29, as noted.

These form an arch over the fire and in proper relation to the opening I in the wall M built across the fire boX as already described, so that the gases, the course of which is controlled by the opening [5, are brought in proper and close proximity to the heating fins and tubes. These are, as noted, attached to the walls of the boiler having intakes attached to the sides thereof and having outlets attached to the overhead crown sheet, the tubes coming from the opposite sides preferably meeting to brace each other and having a common outlet through a single hole in the crown sheet 'I', so as to make only one overhead opening and one set of connections necessary for each pair of tubes.

It is to be understood that as many sets or series of these paired tubes as is necessary are inserted in the boiler in a manner similar to the placing of the cones in Figures 1 and 2. The Water for the intake is again taken through the tubes 2| from the uppermost and super-heated water layer near the top of the boiler and passing through the fin heated tubes escapes through the outlet 19 as steam into the steam chamber l0, and hence on into the heating system before the steaming of the boiler proper occurs.

Where it is desired, as in the case of building a new boiler or reconstructing an old, the wall [4 built across the fire box, instead of being constructed of brick or other refractory material, can be made into a steel or metal water jacket forming a part of the boiler as noted in Figure 8, the jacket, of course, being formed with the opening H5 at the desired point, the same as already described. Where this is used, as in the case of Figures 1 or 2, additional pre-steaming cones or other forms of my similar elements can be attached directly to this cross wall water jacket in addition to the side walls of the fire box at desired points and adjacent to the opening I4.

While in the various Figures 1, 2, 7, 8, 9 and 10, my intercepting wall I4 is shown with a single control opening l5, it is to be understood that I do not limit the construction to a single opening, and where it may be desired, I use two or more such openings located in the wall as desired where the location and construction of the presteaming elements makes it preferable to divide the path of the oxidizing gases and lead them in divergent courses by means of the control openings 15.

Figure 9 shows a modified form of the construction employed in Figure '7, the tubing 28 in this instance having both intakes and outlets attached to the side walls of the water jacket instead of having the outlet in the overhead crown sheet, in this way avoiding over head welding.

In connection with Figures 7 and 9, the fins can be attached to the tubing in any customary manner, but I preferably prefer to braze them and the opposing tubes are also preferably brazed together and to a tie band 3!), so as to give strong rigidity and good heating conductivity to the entire structure. In Figure 9 the heating fins are shown attached to the lower members of tubing close to the fire, but where desired the fins can also be attached to the upper bends of the tube members so as to cover approximately the entire length of the tubular members, and the fins can be formed longitudinally and integral with the tubing walls as well as being added transversely.

In Figure 10, the arrangement of the boiler is somewhat similar to that of Figures '7 and 9 with the exception that in this instance, the presteaming is accomplished by built up finned tubes 3| having finned stiffening members 32 and 33, the exterior walls of the tube being formed by sheet metal walls 34 attached to the fins by rivets or other means, and the whole structure united by brazing. On this finned tube, which acts as a structural supporting member is coiled the tubing [1, the finned tube acting as a structural support for same.

The finned tubes with their coils are connected into the sides of the water jacket and to the intake tube 2| by suitable connections and at the upper end to the walls of the opposite sides of the fire box and to the outlet tube IS in the manner already described in connection with the previous figures, and the pre-steaming occurs in the same way.

The fins 32 and 33 are preferably notched to space and hold the coiling which they support. The whole structure is made of highly conductive metal such as copper, chrome copper or other suitable alloy or metal or combinations of difierent metal, the one supplying high structural strength, as in the fins of the supporting tube, and the other supplying high conductivity, as in the coil or the walls of the fin supporting tube. Steel can be employed, if it is desired, for the structural supporting fins.

The location of the combustion chamber outlet IS in the water jacket partition I4 is arranged in proper relation to the finned tubes 3! and the supported pre-steaming coils ll, so that the radiant heat and burning gases are controlled and brought inproper relation to same. The coiled finned tubes are placed in series the same as in Figure 1 with as many in number as the size of the fire box or combustion chamber permits or makes desirable. The same also applies to the previous Figures 7 and 9. While Figure 10 shows these novel heating tubes extending from one side to the opposite side of the fire combustion chamber, they can be used in various other ways and also connected from the sides of the fire box to the crown sheet after the manner of Figure l,

instead of to the opposite walls.

It is understood that in all the various ways of applying my invention to a boiler, my wall (or water jacket) l4 and the controlling opening l5 can be omitted when desired, as can likewise the interior inlet and outlet tubes l9 and 2| within the water jacket, and my improvements will still greatly enhance the steaming and heating qualities of the boiler as well as secure a great saving in fuel. They can similarly be applied with great advantage to any hot water heating system for accelerating the heating of the water.

Figures 13 and 14 show a modified form of my pre-steaming elements in which copper alloy orother metal tubing of preferably rectangular cross-section with a wide face and a relatively thin thickness is coiled as noted and attached with suitable connections to the water jacket I with the intake 2| and outlet l9 disposed in relation to the water level in the steam chamber, as already described. It is to be noted that the coiled tubing is tipped away from the sides of the water jacket of the fire box at an angle so as to over hang the fire and thereby bring the heating surfaces of the tubing close to the periphery of the body and path of the fire, the longitudinal axis of the tipped coil being determined with this consideration in view and in relation to the 10- cation to my fire exit control openingl5. Tipped in this way, the rectangular tubing presents a fiat face at more nearly right angles to the radiant heat with the result that the heat penetrates directly into the tube instead of glancing ofi, as in the case of round tubing or coiling vertically disposed in the fire box.

In addition to tipping the central axis of the coil outward to over hang the fire, I also preferably tip it forward towards the flow of the fire, as noted in Figure 14. The fiow of the burning gases in this instance passes the tubes from right to left in proceeding out of the fire box. This permits the gas travelling forward to linger longer on the coil as well as contact the rectangular under faces of the tubing at an abrupt angle, so that the heat rays andgases hit the flat faces of the tube at an abrupt or more nearly right angle with the consequent greater. absorption of heat, as compared with ordinary vertical coils of round tubing which have beeninstallgd in fire boxes, but are relatively inefiicient because of their form and vertical position.

I also preferably make the coil with a broader front diameter as noted in Figure 14 than the side diameter as noted in Figure 13, thus giving a broader heating. face presented longitudinally of the fire path. The coil can be stiffened and given greater heating absorption with the fins 23, the same as with my cones heretofore described, and the same as will be noted in Figure 15, and the tubing and fins brazed into a strong. rigid unit.

It is to be understood that these coils are inserted in the boiler in series the same as the cones l6 and in similarly positioned relation to each other and are preferably set on an axis following the path of the oxidizing gases as determined by the exit control opening I5.

While in Figures 13 and 14, the coils are tipped with their upward end farthest outward from the water jacket walls, it is to be understood that the tilting can be reversed as in the case of cones,

IS in Figure 1 so that the lower ends of the coils are farthest out from the water jacket walls and the coils lean toward instead of away from the side Walls of the fire box. Either arrangement can be used at will as condition and preference may dictate.

Figure 15 shows similar heating units formed of rectangular tubing coiled as noted and stiffened with heat absorbing fins 23 preferably brazed thereto. These coils are tipped forward and over the oxidizing zone of the fire as already described for Figures 13 and 14, and in this instance are combined at their intake end with a pre-heating tube 35which receives super-heated water from the upper layer of water as already described, through intake tubes 2| and connecting tubes 38, which connect with the pre-heating tube 35 at its two extremities by suitable connections. These intake tubes 33 at either end of the pre-heater 35 support the structure as noted heretofore, being attached to the sides of the water jacket and are connected by suitable means to the intake tubes 2|. In this arrangement, the tubes are mounted in plurality on the pre-heating tube 35 and the individual outlet ends of each coil are connected to the water jacket with suitable connections connecting with individual outlet tubes I9 which proceed upward to the steam chamber. In this way, the sup-erheated water enters the pre-heater tube 35 through intakes 2|, passes upward through the series of connected coils, producing steam which is carried directly without condensationvthrough the several outlet tubes 19 to, the steam chamber l0. and henceis conducted through the heating system. These, coils are preferably placed in tipped position in relation to the, fire and path of; the oxidizing gases as shown and as already described for the previous forms, and theseries hasits longitudinal axis aligned parallel to the pathof the escaping gases .in relation to control exit 15. with heat absorbing fins 23 of copper or suitable metal and these are shown with the turned out feet 23 brazed to the tubing which is preferably made rectangular throughout the coil. and. left roundat the terminal sections, although this can be .varied at. will.

Figures 16 and1'7 indicate a further modified form similar to that of Figure 15, but in this instance the series of coils are connectednot only to a pre-heater tube 3.5 at their intake but to a similar tube 36 at the top for. outlet, the tubes 35 and 35 being attached with suitable connec tions to vertical end supporting tubes 3'! at either end. of the frame so formed, the whole frame being connectedat the ends with the two lower intake tubes 38and the two upper outlet tubes 39. Thetubes 33 and 39 are connected to the sides of thewater. jacket with suitable connections and connect respectively with the intake tubes 2| and outlet tubes [9 disposed as already described. Thepre-heating tube 35 and the up per outlet tube 36; as well as the end supporting tubes 31, are preferably finned, as noted, to add tothe heattransmission efiiciency. The coil I? i. can be either round, as shown, or of rectangular tubing withor Without fins and the several coils asa unitare tipped outward over the fire and the longitudinal axisof the frame tipped upward paralleling the outward course of the burning gases. toward exit opening 15 corresponding to the arrangement in Figure 15, etc.

In Figures 18 and 19, instead of coiling the,

tubing, I use a series of. straighttubes 40 in combination with fins 4| transversely disposed and also, if desired, provide longitudinal fins c2 formed integrally with the tube or brazed thereto. The tubing, as will be noted in cross-section in Figure 19, ispreferably of rectangular form with a broad, face and narrow thickness, the broad face being disposed over the fire as the finned element is tippediforward away from the water jacket 1. These units are placed in series on the-sides-of the fire box similar to the presteamers already noted and each unit can be formed with multiple tubes as noted, the tubes 4|] being brazed and stiffened by the fins 4!. At their terminal-ends after being received into fittings attaching to the sides of the boiler, these pre-steaming elements connect at their lower ends with intakes 2| and at theupper ends with outlets lawhich proceed upward in the water jacket of'the boiler with terminal locations as heretofore described. The series of pre-steamers are arranged in tipped position and on a diagonal axis in relation to the path of the burning gases passing to the outlet control opening [5, as already described.

Figure 20 shows another arrangement of my presteaming construction as adapted to an oil fired boiler of another popular type on the market. The fire box or combustion chamber 5.in this instance-is fired by a gas burner 3 at its forward end, the projected burning gases being delivered on to the wall I4 in the lower section ofthe combustion chamber from which the ases The coils I! are preferably provided recoil backward and then pass upward and outward through the central control opening to the rear and finally recoil off the rear water jacket I to turn into the boiler tubes 6. In this instance, I locate a large conically formed pre-steaming element of coiled copper alloy or other suitable metal tubing H in the front end of the fire box stiffened with heating fins 23 preferably brazed thereto. This is positioned with its small end towards the oil burner so that the burning and expanding gases pass through the central axis of same. This pre-steamer has its intake tube 2! reaching the upper water of the boiler at its small end and connection and its other outlet end with the outlet tube I9 which passes upward through the boiler to the steam chamber ll). Similarly at the other end of the combustion chamber opposite the control opening I5, I provide a conically formed pre-steamer with its large end so located that the path of the burning gases and the conically coiled element have a common access. This conical coil has its large end located at opening [5 and its small end at the exit end of the combustion chamber, so that by this means, the burning gases are not chilled prematurely by the proximity of the surrounding metal walls before combustion has proceeded to its proper completion. This second pre-steaming coil also has the water intake 2| at its larger end extending upward to the hottest water at the top of the boiler and the outlet tube l9 connecting with the steam chamber from the other or smaller end extending upward to discharge the steam either just above the water line, as shown, or slightly below it where, as already noted, it is found desirable for the water to be able to enter the coil from either direction if necessary. For the additional support of the coil where desired the steel pipe 44 connecting with the water jacket extends through the combustion chamber and through the pre-steaming coil which rests upon it.

It is to be understood that the intake tubes 2i and the outlet tubes [9 located in the water jacket as shown in the various drawings may be omitted at will and the inlets and outlets for the pre-heating or pre-steaming elements secured direct at the points where the coil connections are attached through the wall of the water jacket. This can be done particularly in the case of a hot water heating system. In cases where it is desired also to quickly heat the colder water in the bottom of the water jacket, the intake tubes 2| can be turned downward instead of upward and made to feed the water from the lower points of the water jacket directly into the heating coils thereby producing a more unified water temperature throughout the compartment. It is to be understood, however, that aside from the other distinct advantages already noted from the use of the outlet tubes l9 leading into the upper part of the water compartment or steam chamber so as to avoid any unnecessary condensation of steam in passage, that by this means also surging of the water in the water jacket and the creation of undesirable wet steam is particularly precluded.

It will also be understood that the shape, materials, arrangement, location and connections of my pre-heating or pre-steaming units may be varied at will as desired to meet conditions, and for either a steam or a hot water plant, and for boilers of whatever design and construction.

While I have shown and described my invention in a preferred form, I am aware that various changes and modifications may be made therein without departing from the principles of the invention, the scope of which may be deter- V mined by referring to the appended claims.

I claim as my invention:

1. In combination in a boiler having a combustion chamber and a Water compartment, a single intercepting heat retaining Wall bisecting the combustion chamber and having a control gas exit opening located therein and spaced away from the crown sheet or overhead shell and side walls of the combustion chamber, an automatically controlled firing unit projecting the burning gases through the fire box toward the control opening of the wall, and pre-steaming tubular metallic units connected to the shell of the water compartment and having their axes tilted away from said shell towards the path of the projected burning gases.

2. In a boiler having a combustion chamber and a water compartment, hollow conically shaped quick heating metallic elements attached to the shell of the combustion chamber and having intake and outlet passageways communicating with the water compartment and located adjacent to but not directly in the core ormain path of the burning gases and spaced substantially away from the shell of the combustion chamber, said conical elements having a large opening at one end and a small opening at the other with the large end located at the lower end closer to the fire so as to trap the burning gases and force them through the cone in compression.

3. In combination with a boiler having a combustion chamber and a water jacket, tubular members installed in the fire box connected to the water jacket so as to receive and pre-heat water therefrom, risers formed of tubular coils of quick heating metal supported by and con nected to said tubular members so as to receive and pre-steam the pre-heated water in advance of the steaming of the water jacket of the boiler and means for conveying the steam so generated to the boiler, and a single heat retaining wall located within and across the fire box so as to cause the delay of the burning gases within the fire box in the presence of the quick heating tubular coils, said heat retaining wall being formed of refractory material and having a relatively small exit opening in same whereby the gases finally meet, are compressed, and burned at departure and the temperature of unburned gases chilled by the coils so raised to the burning point.

4. In combination with a boiler having a combustion chamber and a water jacket, longitudinal tubular members installed in the fire box connected to the water jacket so as to receive and pre-heat water therefrom, risers formed of tubular coils of quick heating metal supported by and connected to said tubular members so as to receive and pre-steam the pro-heated water in advance of the steaming of the water jacket of the boiler and means for conveying the steam so generated to the steam chamber of the boiler.

5. In combination with a furnace or the like,

a heating unit fabricated out of tubular metal in coiled formation, the tubular coiling being formed with a changing cross section with substantially rectangular cross section in certain areas and round cross section in other areas.

6. In a'boiler having a combustion chamber and a water compartment, hollow conically shaped quick heating metallic elements attached to the shell of the combustion chamber, the elements being formed with walls of rectangular tubing in stepped formation with the adjacent turns being held in position by embracing fin like ribs which at the same time serve as conductors for increasing the temperature of the tubular walls when exposed to the gases in combustion.

'7. In a boiler having a combustion chamber and a water compartment, hollow conically shaped quick heating metallic elements attached to the shell of the combustion chamber, the elements being formed with tubing with the contiguous turns of the tubing metallically held in relative juxtaposition so as to form a substantially closed shell with a large opening at one end for receiving the burning gases and a small opposing end for discharging the gases in compression.

8. In a boiler having a combustion chamber and a water compartment, pre-heating elements located in the combustion chamber consisting of supporting tubes connecting with the water compartment, said supporting tubes carrying enveloping tubular coils, both coils and supporting tubes communicating with the water compartment.

9. In combination in a boiler having a fire box with a water jacket and having placed in the bed of the fire box a fire pot with its longitudinal sides substantially spaced away from the shell of the water jacket, quick heating tubes mounted in opposing rows substantially spaced away from the side walls of the water jacket to avoid chilling thereby and substantially above the fire pot to avoid undue retarding of initial combustion therein, the units overhanging the vicinity of the sides of the fire pot but with substantial space between the opposing rows to permit of better combustion of the burning gases escaping from the fire pot, the tubes being con-' nected at either end with the shell of the Water jacket so as to communicate with the water for quick heating.

10. In combination in a boiler having a combustion chamber and a water compartment, a single intercepting heat retaining wall bisecting the combustion chamber and having a compression control gas exit opening located therein spaced away from the shell of the combustion chamber, and quick heating metal tubular units located in the combustion chamber above the fire bed and connected to the shell of the water compartment.

11. In combination in a boiler having a combustion chamber and a water compartment, a single intercepting heat retaining wall bisecting the combustion chamber and having a compression control gas exit opening located therein spaced away from the shell of the combustion chamber and quick heating tubular water circulating units connected to the shell of the water compartment and substantially spaced away from the cooling shell of the combustion chamber and likewise from the main core of the burning gases proceeding to the gas exit.

ROY H. ROBINSON. 

